The effect of heat treatment on the front-face fluorescence spectrum of tryptophan in skim milk

Ayala, N.; Zamora, Anna; Rinnan, Åsmund; Saldo, Jordi; Castillo, M.

doi:10.1016/j.jfca.2020.103569

Cited by 17 publications

(19 citation statements)

References 19 publications

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“…Ayala et al [50] also studied the tryptophan fluorescence emission by using frontface fluorescence (56 • configuration, excitation: 290 nm, emission: 300-450 nm) with heat-treated skim-milk powder. Significant changes were observed at 90 and 100 • C. A decrease in tryptophan fluorescence intensity and a red shift was found when the heattreatment intensity increased.…”

Section: B Fluorescence Spectroscopymentioning

confidence: 99%

Thermal Denaturation of Milk Whey Proteins: A Comprehensive Review on Rapid Quantification Methods Being Studied, Developed and Implemented

Freire

Zambrano

Zamora

et al. 2022

Dairy

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Heat treatment of milk signifies a certain degree of protein denaturation, which modifies the functional properties of dairy products. Traditional methods for detecting and quantifying the denaturation of whey proteins are slow, complex and require sample preparation and qualified staff. The world’s current trend is to develop rapid, real-time analytical methods that do not destroy the sample and can be applied on/in-line during processing. This review presents the rapid methods that are being studied, developed and/or applied to determine and quantify the thermal denaturation of whey proteins, including spectroscopic, electrochemical and miniaturized methods. The selected methods save a significant amount of time and money compared to the traditional ones. In addition, the review emphasizes the methods being applied directly to milk and/or that have potential for on/in/at-line application. There are interesting options to quantify thermal denaturation of whey proteins such as biosensors, nanosensors and microchips, which have fast responses and could be automated. In addition, electrochemical sensors are simple to use and portable, while spectroscopy alternatives are suitable for on/in/at-line process.

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Section: B Fluorescence Spectroscopymentioning

confidence: 99%

Thermal Denaturation of Milk Whey Proteins: A Comprehensive Review on Rapid Quantification Methods Being Studied, Developed and Implemented

Freire

Zambrano

Zamora

et al. 2022

Dairy

Self Cite

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“…due to protein-protein association (Lakowicz, 2006). The red shift in tryptophan maxima upon heating was reported to be due to unfolding whey proteins during denaturation, which caused change in the hydrophobicity (Ayala et al, 2020). The decrease in tryptophan fluorescence intensity is attributed to protein-protein interactions between denatured whey proteins with casein micelles (Kulmyrzaev et al, 2005).…”

Section: Size Of Casein Micelle (Nm)mentioning

confidence: 99%

“…Therefore, fluorescence spectroscopy could be an important tool for evaluating heat-induced changes in protein dispersions containing lactose. Ayala et al (2020) applied front-face fluorescence spectroscopy on reconstituted skim milk exposed to heat (70-100°C for 10-60 min) and observed differences in fluorescence spectra of tryptophan, including reduced fluorescence intensity and a red shift. All the above-mentioned studies were conducted on milk or reconstituted milk samples with a protein content of ≤3.5%.…”

Section: Introductionmentioning

confidence: 99%

Effect of pH on heat-induced interactions in high-protein milk dispersions and application of fluorescence spectroscopy in characterizing these changes

Singh

Amamcharla

2021

Journal of Dairy Science

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This study investigated casein-whey protein interactions in high-protein milk dispersions (5% protein wt/ wt) during heating at 90°C for 1.5 to 7.5 min at 3 different pH of 6.5, 6.8, and 7.0, using both conventional methods (gel electrophoresis, physicochemical properties) and fluorescence spectroscopy. Conventional methods confirmed the presence of milk protein aggregates during heating, similar to skim milk. These methods were able to help in understanding the denaturation and aggregation of milk proteins as a function of heat treatment. However, the results from the conventional methods were greatly affected by batch-to-batch variations and, therefore, differentiation could be drawn only in nonheated samples and samples heated for a longer duration. The front-face fluorescence spectroscopy was found to be a useful tool that provided additional information to conventional methods and helped in understanding differences between nonheated, low-, and high-heated samples, along with the type of sample used (derived from liquid or powder milk protein concentrates). At all pH values, tryptophan maxima in nonheated samples derived from powdered milk protein concentrates presented a blue shift in comparison to samples derived from liquid milk protein concentrates, and tryptophan maxima in heated samples presented a red shift. With the heating of the sample, Maillard emission and excitation spectra also showed increases in the peak intensities from 408 to 432 and 260 to 290 nm, respectively. As the level of denaturation increased with heating, a marked differentiation can be seen in the principal component analysis plots of tryptophan, Maillard emission, and excitation spectra, indicating that the front-face fluorescence technique has a potential to monitor and classify samples according to milk protein interactions as a function of pH and heat exposure. Overall, it can be said that the pattern of protein-protein interactions in high-protein dispersions was similar to the observation reported in skim milk systems, and fluorescence spectroscopy with chemometrics can be used as a rapid, nondestructive, and complementary method to conventional methods for following heat-induced changes.

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“…It also allows classifying heated samples according to different temperature treatments (Ahmad and Saleem, 2018). More recently, tryptophan fluorescence was successfully used to discriminate reconstituted skim milk powder samples according to their thermal loads (Ayala et al, 2020).…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

Application of Spectroscopic Techniques to Evaluate Heat Treatments in Milk and Dairy Products: an Overview of the Last Decade

Aït‐Kaddour

Hassoun

Bord

et al. 2021

Food Bioprocess Technol

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In the food industry, thermal treatments are generally an essential step to increase the shelf life of the products. This is especially true for milk and dairy products in which heat treatments help to eliminate pathogenic organisms, minimize microbiological development, and improve some sensory properties. However, they can also induce biochemical, physico-chemical, and sensory changes in foods, and then adversely affect the final quality of the products. To assess the quality of milk and dairy products during heating, some nondestructive techniques exist. In this article, the application of spectroscopic non-destructive techniques (fluorescence, infrared, NMR) is analyzed to point out the pertinence by using them as tools to monitor milk and dairy product quality changes during heating. An overview of the last studies on the effect of different conventional and emerging methods of milk and dairy product heating on biochemical, physico-chemical, and sensory quality is also presented, as well as the perspectives of research in this topic.

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The effect of heat treatment on the front-face fluorescence spectrum of tryptophan in skim milk

Cited by 17 publications

References 19 publications

Thermal Denaturation of Milk Whey Proteins: A Comprehensive Review on Rapid Quantification Methods Being Studied, Developed and Implemented

Thermal Denaturation of Milk Whey Proteins: A Comprehensive Review on Rapid Quantification Methods Being Studied, Developed and Implemented

Effect of pH on heat-induced interactions in high-protein milk dispersions and application of fluorescence spectroscopy in characterizing these changes

Application of Spectroscopic Techniques to Evaluate Heat Treatments in Milk and Dairy Products: an Overview of the Last Decade

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